St. Louis’s well-known monument, the “Gateway Arch to the West,” was completed 50 years ago. Architect Eero Saarinen designed it to honor the pioneers who moved west. But did you know that the Arch also shows some important scientific discoveries? The monument’s shape is called a catenary arch. This shape usually forms when a chain hangs freely from two ends, like a draping necklace. When turned upside down, this shape can support its own weight. This lets the arch stand 630 feet (192 m) tall without supports. Also, the Gateway Arch is made from a mixture of steel and chromium. The chromium creates a thin coating over the steel, which keeps the arch from rusting. It took scientists many years to discover this mixture.
Photo of the Gateway Arch by Rick Watson/Flickr Creative Commons.